Drawing-board



H. DE CLERCQ.

DRAWING BOARD.

APPLICATION FILED MAY 7, 1920.

Patented. July 13, 1920.

Inventon W {,Au fl qf.

Attorney PATENT OFFICE.

HENDRIK DE CLERCQ, OF AMSTERDAM, NETHERLANDS.

DRAWING-BOARD.

Specification of Letters Patent.

Patented July 13, 1920.

Application filed May 7, 1920. Serial No. 379,611.

To all whom it may concern.-

lle it known that I, I-IENDRIK on CLERG a subject of the Queen of Holland, residing at Amsterdam, Transvaalstraat 60, Netherlands, have invented certain new and useful Improvements in Drawing-Boards, of which the following is a specification.

The present invention relates to a drawing board in combination with a ruler connected with two endless chains led around guide wheels, said ruler being adapted to be moved over the board in parallel relation with itself. The object of the invention is an arrangement wherein practically only the top edge of the ruler is pressed with adjustable pressure against the board so that it requires only a very small force to move the ruler by hand over the board. With this object in View the invention principally consists in that each end of the ruler is connected by screws with two points of the corresponding chain disposed at a certain distance apart, in such a manner that the distances between the ruler and the points in which said screws engage the chain may be adjusted so as to produce an angle in the chain, and consequently a couple tending to press the top edge of the ruler against the board.

In order that the invention may be better understood, reference is had to the accompanying drawing in which Figure 1 is a perspective view of a drawing board constructed in accordance with the invention, and Fig. 2 is a somewhat diagrammatic side view of part of the board, on an enlarged scale.

In the drawing, 1 is the drawing board having at both sides two chain wheels 2 and The wheels 2 are mounted on a shaft 11 supported at some vertical distance above and at the rear side of the board, and the wheels 3 are rotatable about axes connected with coiled springs 4 tending to pull said wheels downward, an endless chain 5 being led around each pair of wheels 2, 8.

The ruler 6 has fixed to it at both ends two screws 7, 8 spaced a certain vertical distance apart, each of said screws projecting through a link of the corresponding chain 5. A nut 9 on the screw 7 is provided at the rear side and a nut 10 on the screw 8 is provided at the front side of the front part of the chain.

From the drawing it will be readily understood how the distances between the ruler and those points, wherein the screws 7, 8 through their nuts 9, 10 engage the chains, may be adjusted in such a manner that in each chain are formed two angles pointing inward and outward respectively, thereby producing a couple which tends to press the top edge of the ruler against, and to draw the bottom edge of the ruler away from the board. Owing to this arrangement, the top edge of the ruler which serves to guide the draftsmans pencil or drawing pen is always in close contact with the board (provided always that the tension of the springs 4 and the positions of the nuts 9, 10 are correctly adjusted) and yet the frictional re sistance between the board and the ruler is so low that a displacement of the ruler over the board does not require any appreciable force.

Claim.

In combination, a drawing board, guide wheels connected with said board at both sides thereof, endless chains led around said wheels, a ruler both ends of which'are associated with said chains so as to be adapted to be moved over the board in parallel relation with itself, screws fixed in the ruler to connect each end thereof with two points of the corresponding chain in two points suitably spaced apart, and nuts on said screws by which the distances between the ruler and the points wherein said screws engage their chain may be so adjusted as to produce an angle in said chain, and consequently a couple tending to press the top edge of the ruler against the board.

In testimony whereof I affix my si nature.

HENDRIK DE CLEltCQ. 

